Article sorting control apparatus



May 22, 1952 G. HlRscHFELD TAL 3,035,694

ARTICLE soRTING CONTROL APPARATUS 3 Sheets-Sheet 1 Filed April 4, 1958 mwu May 22, 1962 G. HlRscHFx-:LD ETAL 3,035,694

ARTICLE SORTING CONTROL APPARATUS 3 Sheets-Sheet 2 Filed April 4, 1958 G. HlRscHFELD ET A1. 3,035,694

ARTICLE SORTING CONTROL APPARATUS May 22, 1962 3 Sheets-Sheet 3 Filed April 4, 195s GERHARO H/RscH/-ew wea/ven H//vz BY HANS/675A FR/rzscwe' MM2/v AGENT United States Patent O 3,035,694 ARTICLE SGRTIN G CONTROL APPARATUS Gerhard Hirschfeld, Berlin, Werner Hinz, Berlin-Neukolln, and Hanspeter Fritzsche, Berlin-Friedenau, Germany, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Dela- Ware Filed Apr. 4, 1958, Ser. No. 726,405 Claims priority, application Germany Apr. 9, 1957 18 Claims. (Cl. 209-75) This invention relates to sorting machines and more particularly to improvements in apparatus for sorting articles under control of and in accordance with the location of a characteristic mark thereon.

In the treatment of legendized papers it is often necessary that marks athxed on them be heeded. This is especially so in mail sorting and processing systems where post letters are to be sorted according to their destinations. Since the letters when passing by the sorting operator must be in proper position for reading, it is convenient for them to be so positioned that the postage stamps on the letters may always appear in the same position, preferably in the upper right hand corner as viewed by the operator. The presence of the marks, that is, of the stamps in the Vcase of letters, is ascertained in well-known manner through testing by means of photoelectric or electronoptical equipment past which the papers constantly move. After such testing has been etected, the papers are conveyed into predetermined channels in which they are either collected in receptacles or turned over, depending on their position, whereupon they are conducted into a channel common to them.

These arrangements, to which the invention relates, must be able to deal with letters, or other such papers, of different sizes, and therefore involve a great expenditure in apparatus because the papers and hence the marks on them can be in any one of four positions with respect to the test device while between these still other positions of the papers are possible. The invention is to considerably reduce this expenditure in apparatus without impairing in any degree the reliability of service.

The invention concerns a method by which the presence of a mark aihxed on a legendized or inscribed paper, and in particular the presence of a postage stamp atiixed on a letter envelope, shall be ascertained by means of photoelectric test devices past which the paper is moved continuously and which control evaluating circuit-arrangements that, in accordance with the result of the test operation, produce an output signal for initiating a control action. This control action serves the further treatment of the paper and, eventually, is effective in respect of con- -tinued conveyance of the paper.

The invention consists in connecting more than one of a plurality of test devices in succession to a common evalnation equipment.

According to a further feature of the invention, only those test devices are actuated which will be within the Width limitations ofthe paper and thus apt to ascertain the mark. The test device is switched on dependent upon either the front or the rear edge of the paper as viewed in the directionV of motion, i.e. the edge near the mark, but is not switched on dependent upon the length of the paper.

The test devices, controlled by the photoelectric limit detectors of the measuring device, are so switched on in succession that as soon as one such device is switched ott the next following test device will be switched on.

In order to prevent the upright edges of the ,paper from causing the test device to produce a signal,i each paper is tested during a period that begins immediately after the front edge of this paper has reached the test device. and

3,035,694 Patented May 22, 1962 nishes before this has been reached by the rear edge of the paper. Appropriately the arrangement is such that the area not swept over by the respective test device is about from 3 to 5 millimeters from either of these two edges.

Moreover, to decrease the number of test means and to lessen the time of testing, merely that area of the paper should be tested in which the mark will most probably be contained. In the case of letters this area is always outside a center portion thereof. Besides, depending on the position of the letter the stamp may be either in the upper right-hand corner or in the lower left-hand corner. Therefore it is sutlicient for each paper to be tested only along a length of it that does not extend from the edges quite to the middle of the paper. The testing may thus extend from the right-hand upper corner toward the center line without reaching this, and from a point of the lower lefthand corner toward the left-hand edge, this point being spaced from the center line.

The test devices are displaced vertically with respect to each other so as to scan the desired portions of the papers of various widths that will in all probability have to be dealt with. Moreover, the test devices are oifset longitudinally with respect to one another and are mutually offset by the length of the path to be tested, so when the paper is passing by the test devices the testing actions of the respective paths follow upon each other closely. For testing the upper part of the paper, from two to four test paths or test devices will in most cases be necessary, whereas in respect of the lower part one or two test paths or test devices will suice.

In order to prevent wrong switching, a measuring device is arranged to cause all the test devices to be ineffective whenever there is no letter in the respective test device, that is to say, the test device shall not be operated by the measuring device until a letter passes the measuring device.

The devices employed to test the upper parts or the upper right-hand corners of the letters are combined into a group, rand those for testing the lower parts or the lower left-hand corners thereof are combined into a second group. Since the backside of each paper must likewise be scanned as to a mark, still another test device, similar to those herebefore mentioned, must be provided. In a certain case, on which the paper can happen to be in any one of more than four posi-tions, namely, if letters to be sorted are not only rectangular but in the shape of a square so that al1 the edges of each such letter are of the same length, additional test devices will be necessary. But in most cases the arrangement may be such as to deal with none but four positions of the papers, these generally being rectangular and not in the shape of a square.

Each group of test devices on -nding a mark produces an output signal'which acts then to clear the path assigned to this group, whereupon the paper may move along this path. If, however, marks are ascertained by devices serving to test various areas of two or more groups, then this indicates one of the ascertainments to be wrong. Accordingly the path for the paper will be so controlled as to lead this paper into a separate channel not assigned to any one of the groups. This channel thus receives all the papers which on account of their state can not be clearly identified by the test device.

A special device is arranged to measure width and length of the papers before these enter the test equipment, and also to measure the mutual distance of two papers following upon one another. Whenever this measuring device finds that distance to be less than a certain value, the papers thus spaced too little apart shall be eliminated from the further treatment. They will be collected separately and may later be again subjected to the action of the test device, just as those papers whose dimensions are beyond a certain width or a certain length.

Moreover, the entire installation must be supervised by a separate measuring device as to whether the number of the incoming papers agree'with that of the outgoing papers. Any difference between the two valueswill mean that a paper has gotten caught or entangled and that consequently the conveyance of the papers succeeding has been endangered. The measuring device must be able then to stop the installation and to send a Warning signal in order that the fault may be removed.

The invention will be explained hereafter with the aid of an example represented in the drawings.

The arrangement there shown serves to so position letters, arriving in any order, so that they shall be in proper position for reading.

FIG. l is a block diagram of the entire installation;

FIG. 2 is a circuit diagram of the control equipment comprising the test device, and also illustrates the means by which this device is changed over to the evaluating circuit-arrangements.

FIG. 2a is a schematic detail view of one of the test devices; and

FIG. 3 is a circuit diagram representing the device employed to measure the mutual distance of two letters following upon one another.

In the arrangement according to FIG. 1 the letters to be sorted arrive at Q on a conveyor system designated by the heavy line. -They are so positioned that their longitudinal edges extend in the direction in which the letters are moved. Assume that each letter has the postage stamp affixed' on it in the right-hand upper corner, then the letters may each be in any one of four positions. As viewed in the direction of motion, the two faces of the letters may be spoken of as the right-hand side and the left-hand side thereof. Accordingly the said four positions of the letters may be defined as follows:

l) Stamp on the right-hand side and in the right-hand upper corner as viewed looking toward the right hand side of the letter.

(2') Stamp on the right-hand side and in the left-hand lower corner as viewed looking toward the right hand side of the letter.

(3) Stamp on the left-hand side and in the right-hand upper corner'as viewed looking toward the left hand side of the letter.

(4) Stamp on the left-hand side and in the left-hand lower corner as viewed looking toward the left hand side of the letter.

The letters are in succession supplied by the conveyor, not shown, to a measuring device B as shown in IFIG. l, (the details of which are shown in FIG. 3) which they reach after having been spaced at certain distances apart. The device B contains photoelectric detectors or lightbarriers L10, L20 L60 that each comprise a source of light and a photoelectric cell arranged on opposite sides of the conveying path. The outputs of the photoelectric detectors are connected with an evaluating circuit C the details of which are shown in FIG. 3 and which then acts to set a routing switch Wo wheneverV the letters are larger than a certain size, or if the distance Vbetween two letters be too small. These letters are shuntedalong path S2 to be disposed of, as'will be later described. The letters that have proved correct as to size and mutual distance are conveyed along the path S1 and then arrive vat 'test devices E and test devices'F disposed on opposite sides of the conveying path. The devices Eserve'to scan the right-hand side of each letter. The devices F are arranged to scan the left-hand side thereof. The devices E, F are 'oisetwith respect `to each other; Their outputs are connected with circuit G1, G2, and G3, G4 respectively that serve to evaluate or utilize the scansion result furnished by each letter. VSuch scansion-evaluating circuits are each Vprovided for two or more of the test devices E, F. Only four of these scansion-evaluating circuits G1-G4 are shown. The combination of test devices E can be joined to the circuits (l1-G4 by change-over equipment H1, the combination of test devices F can also be joined to G1-G4 by change-over equipment H2. The changingover to the results from the individual scanners E and F is controlled by the test devices themselves, as well as by a group L of photoelectric limit detectors L1-L6 and a group K of photoelectric limit detectors lil-K6. Over register equipment R the scansion-evaluating circuits are connected via a control device x for a routing switch W1, while over additional register equipment S they are in circuit-connection with a control device Y'for a routing switch W2. The switches W1, W2 are allocated to the outputs of the test devices E, `1:" and are arranged to be set by the evaluating circuits, such as G1-G4, in accordance with that position of a stamp that has been ascertained by the test devices E, F. If no clear test result is obtained, or if two test signals are produced, then the routing switches W1, W2 will be so set that the respective letter shall be deposited into a reject receptacle Z. The outlet paths of the switches W1, W2 may be so arranged as to lead into outlets M, N common to them. Also, means are arranged to check whether a mark has been ascertained several times. These means are so connected with each other that in such event the routing switches shall be so set as to lead into receptacle Z.

The individual scanners, P1, P2-P6 and E1, E2, E3 and E., all located in test device E, working in cooperation with light sources L1-Ls, examine the right hand side of the letters which pass thru path S1 as viewed looking in the direction of travel of the letters toward switch W1. Likewise another complete set of similar individual scanners located in test device F and cooperating with light sources K1-K6 serve to examine the left-hand side of letters passing thru path S1 toward switch W1. The test device F controls switch W2 ultimately. The test device E controls switch W1 ultimately. In this manner the switches W1 and W2 are operated to divert all letters with a common orientation into a common receptacle such as M or N. The paths S3 and S4 may contain other mechanisms which perform some intermediate operation on the letters in these paths before the letters are recombined at M or at N. These other mechanisms might invert the letters o1' cancel the stamps for example. These other possible mechanisms in paths S3 and S1 are not shown and do not form any part of the novelty of our invention. The test devices E and F simply show how to divert letters into any one of live paths according to the presence and location of the stamps on the letters and the height and length of the letters.

In FIG. 2 the details of the E test device of FIG. l are shown. It will be understood that there is a similar group of test circuits (not shown) for the F test device of FIG. 1. The test circuits El, E2, E3, E4 are shown, each of which comprises a photoelectric cell F1, F2, F3, F4 connected to amplifiers V1, V2, V3, V4 respectively, op erating as cathode followers. This arrangement is necessary in order to achieve a low impedance output from the test circuit. Coupled to the cathodes of the tubes V1-V4 are the base electrodes of transistors T1, T2, T3, T4 respectively, arranged to amplify the photocell signals. The collector electrodes of the transistors T1-T4 are connected in common to a common load resistance R5. The output of said transistors appears across said resistance. Only one transistor will be eifective at a time. The collector electrodes are alsoV connected to terminal a of an apparatus A that serves to ascertain, from the information of these signals, whether or not the desired signal was existing, this being indicated by a pulse at the output terminal e of apparatus A. This arrangementis not a subject of the present invention but of that according to applicants copending application filed =April 4, v1958, Serial No. 726,475.

FIG. 2a is a schematic representation showing how the photocells lFit-F4 are disposed in the test device E past which the paper to be scanned is moved uniformly in the direction of the arrow. From this representation it appears that F2 is situated above F4 while 1-"1 is situated above F3, and that each of these cells is at a diierent level from the other cells. The cells F2, F4 are spaced from F1, F3 by the length of the scansion path. Disposed in this test device E are still other photoelectric elements, namely phototransistors P1-P6. P1, P6, P5 are in vertical alignment with the cells F2, F4. The transistors P1, P2, P3, P4 are in a straight line that extends in the direction of motion, and are spaced apart at distances equal to the scansion length.

These transistors P1-P6 are also represented in FIG. 2, in conjunction with their associated sources of light lll-L6, and are situated on one side of the path S1 along which the paper to be scanned is moved as indicated by the arrow. The sources of light L1-L6 are on the other side thereof. The transistors P1-P6 are normally caused to conduct due to their photoelectric characteristics.

The output signals of P1-P6 are applied to a circuit arrangement in lorder there to operate one of the transistor amplifiers T1-T4, the position of the paper determining which of these shall be operated. Assume that the transistors employed are of the type p-n-p and that the potential of the voltage sources U1-U7 increases with the index numbers 1 to 7, so that U1 has the least, U7 the highest potential. Since each transistor P1-P6 conducts the relatively high potential U6 appears on the collector electrodes thereof.

Vhen a paper moving along path S1 passes between the sources of light L1-L6 on the one hand and the associated phototransistors on the other hand, then, depending on the headroom of this paper each phototransistor which with respect to the headroom of the paper is not too high above path S1 will be darkened by the paper intervening between this transistor and the appertaining one of the sources of light L1-L6. Transistor P1 will thus be darkened in each case, and will cease -to conduct. Consequently, the potential across diodes D4, D falls and is now less than that of the voltage source U4. Transistor T6 will now conduct. Transistor P2 is still exposed to light and diodes D1, D7 conduct over an obvious path. Accordingly, the potential U6 on the base of transistor T9 is higher than that of voltage source U5. Transistor T9 is thus normally blocked, so the potential across diodes D5, D11 is likewise less than that of voltage source U4. Diode D is normally blocked since its associated transistor T13 is normally blocked. Thus with diodes D10, D11 and D12 blocked, transistor T8 may become conductive if a voltage appears on the base electrode of its corresponding transistor T4. lf, for example, a paper is of such a headroom as to darken not only transistor P1 but transistor P6 too, whereas P5 remains lighted, then transistor P6 will likewise be blocked and transistor T12 will conduct. Diode D6 thus acquires -a potential which is lower, diode D12 a potential which is higher than that of Voltage source U4. In this way the three diodes D4, D5, D6 in the base branch of transistor T6 have been biassed negatively and thus blocked. Transistor T6 hence becomes conductive over resistance R8 so that the potential of voltage source U4 passes to the collector of this transistor T6, whereby the amplifier transistor T2 will be effective in the evaluating equipment A. Owing to the fact that the diode D12 has the voltage U5 applied to it through transistor T12 that has been made conductive by the blocking of transistor P6, this potential will be eiective to normally maintain transistor T8 in non-conducting condition.

The paper in motion continues along its path to darken and thereby to block the phototransistor P2. Voltage U6 is no longer eectively applied to the base of transistor T9 and transistor T9 is thus rendered conductive. Diode DS hence acquires the potential U5 which is higher than that of the source U4 and becomes etfective at the base of transistor T6 to block sarne and to disconnect the amplier T2. Transistor P2 having been blocked, the potential at the diodes D1, D7 is lower than that of voltage source U4. The normal conduction of phototransistor P3 blocks the transistor T10, whereby the potential at the diodes D2, D8 will be lower than that of U4. Thus, the transistors T5, T7 can now be rendered conductive dependent on the diodes D3, D9. If, as stated by way of example, the phototransistor P5 remains exposed to light while transistor P6 is darkened, then transistor T11 will remain blocked since :transistor P5 remains conducting, because voltage U6 etectively blocks transistor T11 over transistor P5 and resistance R21. Accordingly, diode D3 now has a potential higher than voltage U4, diode D9 a potential lower than this. Consequently only transistor T7 and not transistor T5 can be rendered conducting, T7 being fed with voltage U1 over resistance R7, whereas to the base of transistor T5 the potential U6 is applied over diode D3 now conductive and over transistor P5 now conducting. Hence transistor T5 is cut oi While at the evaluation equipment A merely a signal under control of transistor T3 is effective.

The paper continues along its path to darken the phototransistor P3, which is thereby blocked. Transistor T10 is rendered conductive over the resistances R20, R13. Diode D8 acquires a potential U6 which is higher than vol-tage U4 and becomes effective at the base of transistor T7 to Iblock this transistor. In this way the amplifier transistors T1-T4 are prevented from operating by vthe normally blocked transistors TS-TS.

When the evaluating equipment A receives, over one of the transistors T1-T4, a signal denoting the detection of the characteristic marking (i.e. a postage stamp) a positive voltage step appears at its output terminal e. This voltage step is differentiated by condenser C3 and charges the register Sp1. Thereby normally conducting transistor T14 of register Sp1 is blocked and transistor T13 thereof is rendered conducting. The output terminal n of register Sp1 has thus nearly reached the potential U1. When the paper then traverses the light-barrier L4-P4, the variation of brightness which the phototransistor P4 thereby undergoes relatively slowly will cause, overa well-known trigger circuit J, a positive potential variation to arise abruptly at the output terminal b of this circuit. This variation is diierentiated by ycondenser C1. The positive pulse, eiec-tive over diode D14, causes a reset ofthe register Sp1. Thereby a positive voltage step larises at terminal n of Sp1. This step is differentiated by condenser C4 and acts to charge the register Sp2 wherein the normally conducting transistor T15 is blocked and transistor T16 rendered conducting. In this way a blocking potential higher than that of the voltage source U2 is applied to transistor T18, `and transistor T17 is rendered conducting over resistance R27. Transistor T17 hence closes the circuit of the setting magnet M1 which controls the routing switch W1 in order to have the paper introduced into the conveying path 54.

If, while the paper is passing by the phototransistors P1, P2, P3, no signal signifying the presence of a characteristic marking has reached the evaluating equipment A, then no positive potential variation results at terminal e thereof and register Sp1 therefore remains at rest. Terminal n cf Sp1 is at the potential U3. When the paper is passing through the light-barrier L4-P4 the positive potential variation at terminal b of circuit I will not aifect the register Sp1 if transistor T13 thereof has not been caused to conduct. As, however, the potential of terminal n is applied over resistance R26 and thence to condenser C2 and diode D16, these hence not being biassed negatively, the potential variation at terminal b of circuit I can be differentiated by condenser C2 and act over diode D16 to discharge the register Sp2. Consequently, the transistors T17, T18 change their state so that the setting magnet M2 for the routing switch W will be energized and the setting magnet M1 be disconnected. The paper shall thus be introduced into the conveying `path S3.

For having the paper scanned at other locations thereof than that here assumed, the photoelectric cells Flr-F4 and the photo transistors Pil-P6 as well as the vdiodes`D1-D12 of the evaluating equipment must be arranged differently from what is shown here.

FlG. 3 represents an arrangement by which the papers when in the conveying path S shall be checked as to their'dirnensions and mutual distances. This measuring path comprises photo-electric detectors L10, P-L60, P60. The detector L60-, P60 is to supervise each paper as to its headroom and is therefore at the requisite level above path S0. The detectors L10, P10-L50, P50, arranged in a row, are only so high above S0 that each paper shall cooperate with them. The distance between Lit?, P10 and L20, P20, as well as that between L40, P40 and L50, P50 check the distances between the individual papers. Whenever the mutual distance between two or more papers is too small, these must be detlected `into path S2. The arrangement according to FiG. 3 is in the converging path and is pre-connected to that represented in FIG. 2 so that all the papers entering the path S1 have been tested by the measuring equipment, FIG. 3. The equipment of FIG. 3 is designated in FIG. l as B and C. The potential designated as U10-U60 in FIG. 3 increases according to the index numbers 10-60.

Each paper of undue length will darken all the normally conducting phototransistors P10-P40 causing them to cut olf. Consequently, the collectors of these transistors acquire the potential U10 eiective over R10, R20, R30, R40, while the diodes D10, D20, D30, D40 will be biassed negatively, thus causing the diode D50 to open and register Spit) to be charged over resistance R70 and diode D50. In this way transistor T10 of this register is rendered conductive while normally conducting transistor T20 thereof is blocked. Thereby at point a0 of register Sp10, the potential U40, and at point b0 thereof, potential U10 arises. Diode D10a is thus biassed positively, diode D13 biassed negatively. The paper then comes to darken the phototransistor P50 to block it, with the result that in gate G50 the diodes D13, D12 have been biassed negatively, so that over resistance R11 and diode D15 the register Sp2() will be charged. Therefore, in this register the transistor T40 is conductive while transistor T30 has been blocked. Transistor T50, coupled to register Sp20, acts to operate the magnet M which in turn, controls the routing switch W0 and thus causes the paper to be introduced into path S2. After the paper has traversed the photoelectric detectors L40, P40 and L50, P50, the transistors P40 and P50 are again under the influence of light and are hence conductive. Accordingly the diodes D70, D80 are biassed positively so that Vtransistor T79 acquires at its oase the potential U60 etfective over resistance RSG. Thereby transistor T70 is blocked and register Sp1() discharged over resistance R90 and diode D90. The points a0, bt) of register Sp1@ change their state. if then a paper of normal dimensions traverses the detector L50, P50, then in gate G40 the diodes Dltla, D11 will be biassed negatively, so register Spf/".0 discharges over resistance R100 and diode D14. The transistors T50, T50 change their state so that magnet -Mll becomes energized and ma net M20 deenergized in order that the routing switch W0 may be set to lead this paper into path S1.

When a paper of abnormal height moves along path S0, the phototransistor P69 will be darkened by it and thus be blocked. (Ever resistance R60 and diode D60 the register Sp1() is hence charged. As soon as the paper traverses the detector L50, P50 the operations thereby initiated are the same as those herebefore described for a paper ofrexcessive length,'so the paper of excessive height lwill likewise be led into path S2.

` if the mutual distance of two papers moving along Vpath Sil is too small, being such that at a certain moment Y all the phototransistors P10-P40 are darkened, then this Y is equivalent to the arrival of a letter of excessive length.

f) it Accordingly, the rst of the two papers through traversing .the detector L50, P50 causes the routing switch W0 to be set. However, before the second paper arrives at this detector the two transistors P40, PSG will be caused to reconduct successively, so that both of the diodes D, Dsl,`v will not be simultaneously biassed positively and the register S1710 w'll hence not be discharged as r erebefore described. Consequently, by the second paper traversing the detector L50, P50, the routing switch W 0 remains in the position into which it has been brought by the rst paper. The second paper will thus likewise be led into path S2.

lf this second paper is followed by one spaced at a normal distance therefrom, then, before this third paper comes to traverse the detector L50, P50, the phototransistors P40, P50 will be simultaneously exposed to light from their associated sources L40, L50, respectively. Register S1110 is thereby discharged in a manner known to those skilled in the art. Therefore, the detector L50, P50 when now traversed by that third carrier causes the routing switch W0 to be so set as to introduce Ythis paper into path S1.

While we have described above the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

l. Article sorting apparatus comprising a plurality of receptacles, conveyor means for conveying articles to said receptacles, said conveyor means including switch means for selectively delivering articles to predetermined of said receptacles, rst detecting means adjacent said conveyor means for detecting the presence and size of an article carried by said conveyor means, additional detecting means adjacent said conveyor means for detecting the presence and location of distinctive markings carried by said articles, control means for controlling operation of said switch means, said control means comprising means responsive to the operation of said first detecting means for conditioning said control means for response to the operation of said addi-tional detecting means whereby said articles are selectively routed to appropriate .of said receptacles dependent upon the size of the article and the presence and location of said marking thereon, said additional detecting means comprising a second plurality of spaced, radiant energy-responsive elements, a second plurality of additional sources of radiant energy, each additional source in cooperating position with a different one of said second radiant energy-responsive elements, each of said articles adapted to interrupt the cooperation of 'at least one of said additional sources with its associated element as it is transported by said conveyor means and in accordance with the position of the distinctive marking thereon, said control means forrcontrolling operation of said switch means comprising an evaluating circuit, a plurality of amplifiers, each coupled intermediate a diierent one of the radiant energy-responsive elements of said first detecting means and said evaluating circuit, gate means under control of at least two of the radiant energy-responsive elements of said additional detecting means, said gate means comprises a plurality of rectifiersY arranged in `a matrix and coupled intermediate radiant-responsive elcmen-ts of said additional detecting means and said ampli- Vfiers. Y Y

2. Article sorting apparatus as claimed in claim l, whereinY said gate means further comprises a plurality of static switch elements, each such switch element intermediate said matrix and a different one of said ampliers.

3. Article sorting apparatus as claimed in claim 2, wherein said matrix is connected in a manner whereby the Y operation of the iirst of the radiant energy-responsive ele- 4. Article sorting apparatus as claimed in claim 3, wherein said matr-in is connected in a manner whereby each article is tested by said additional detecting means during the interval of time required by an article to pass between 1the rst and the ultimate radiant energy-responsive elements of said first detecting means.

5. Article sorting apparatus as claimed in claim 4, wherein said additional detecting means is positioned to scan a predetermined portion of an article conveyed by said conveying means, said portion extending from the adjacent edges of said article.

6. Article sorting apparatus as claimed in claim 3, wherein -adjacent of the radiant energy-responsive elements of said irst detecting means are spaced a distance suicient to measure the distance between two adjacent articles conveyed by said conveying means.

7. Article sorting apparatus as claimed in claim 6, wherein adjacent of the radiant energy-responsive elements of said iirst detecting means are spaced a distance suicient to detect a distance between adjacent articles car-ried by said conveying means, which distance is smaller than a predetermined amount.

8. Article sorting apparatus as claimed in claim 3, wherein said matrix is connected in a manner 'to preclude operation of said additional detecting means when no article is detected by said first detecting means.

9. Article sorting apparatus comprising a plurality of receptacles, conveyor means for conveying articles to said receptacles, said conveyor means including switch means for selectively delivering articles to predetermined of said receptacles, irst detecting means adjacent said conveyor means for detecting the presence and size of an article carried by said conveyor means, additional detecting means adjacent said conveyor means for detecting the presence and location of distinctive markings carried by said articles, control means for'controlling operation of said switch means, said control means comprising means responsive to the operation of said first detecting means for conditioning said control means for response to the operation of said additional detecting means whereby said articles are selectively routed to appropriate of said receptacles dependent upon the size of the article and the presence and location of said marking thereon, said conveyor means comprising a main conveyor and a plurality of auxiliary conveyors, said auxiliary conveyors intermediate said main conveyor and diierent ones of said receptacles, said rst detecting means comprising a rst plurality of spaced radiant energy-responsive elements, a plurality of sources of radiant energy, each source in cooperating position with a dierent one of said radiant energy-responsive elements, said articles adapted to interrupt the cooperation of said sources with its associated element as it is transported by said main conveyor in accordance with its length and height, said control means for controlling operation of said switch means comprising an evaluating circuit, a plurality of ampliers, each coupled intermediate a different one of the radiant energyresponsive elements of said rst detecting means and said evaluating circuit, and gate means under control of said second detecting means for conditioning said amplifiers for operation.

10. Article sorting apparatus comprising a plurality of receptacles, a conveyor for conveying articles to said receptacles, said conveyor including a plurality of switches for selectively delivering articles to predetermined of said receptacles, rst detecting means adjacent said conveyor for detecting the presence and length of articles carried by said conveyor, second detecting means adjacent said conveyor for detecting the presence and height of said articles, additional detecting means adjacent said conveyor for detecting the presence and location of distinctive markings carried by said articles, a lirst switch of said plurality of switches disposed in said conveyor preceding said additional detecting means, first control means for controlling operation of said rst switch and responsive to both said rst and said second detecting means, said first control means operating said tirst switch so that only articles of predetermined suitable length and height are conveyed past said additional detecting means whereby said articles are selectively routed to appropriate of said receptacles dependent upon the length and height of the article and the presence and location of the said marking thereon.

11. Article sorting apparatus according to claim 10 wherein said rst detecting means comprises a rst plurality of radiant energy responsive elements spaced in predetermined relationship With each other, `a plurality of sources of radiant energy, each source in cooperating position with a different one of said radiant energy responsive elements, said second detecting means comprising at least one radiant energy responsive element spaced in predetermined relationship with said conveyor, at least one other source of radiant energy, each said other source in cooperating position with a different one of said radiant energy responsive elements of said second detecting means, said first control means comprises gating means coupled to each of said elements of said first and second detecting means and trigger means coupled intermediate said gating means and said rst switch.

l2. Article sorting apparatus according to claim ll wherein said additional detecting means comprises a iirst group of spaced radiant energy responsive elements and a rst group of sources of radiant energy each source in cooperating position with a different one of said radiant energy responsive elements of said first group, a second group comprising a plurality of radiant energy responsive elements, all of said elements in said additional detecting means being in predetermined spaced relationship with each other and said conveyor, second control means coupled intermediate said additional detecting means and the remainder of the switches of said plurality of switches, said second control means comprising an evaluating circuit, a plurality of ampliiers each coupled intermediate a diierent lone of the radiant energy responsive elements of said second group of said additional detecting means and said evaluating circuit, and gate means under control of said lirst group of elements for conditioning said amplifiers for operation.

13. Article sorting apparatus comprising a plurality of receptacles, a conveyor for conveying articles to said receptacles, said conveyor including a plurality of switches for selectively delivering articles to predetermined of said receptacles, iirst detecting means adjacent said conveyor for detecting the height of an article carried by said conveyor, second detecting means adjacent said conveyor to detect the length of the article and the position of the article along the conveyor path, a plurality of individual scanners for 4detecting the presence and location of distinctive markings carried on said article disposed in predetermined relationship to said first and second detecting means and said conveyor, logic means coupled intermediate said iirst and second detecting means and said individual scanners to simultaneously select particular ones of said individual scanners to examine only particular areas on said article for the presence of said marking depending on the length and height and position of said article.

14. Article sorting apparatus comprising a plurality of receptacles, a conveyor for conveying articles to said receptacles, said conveyor including a plurality of switches for selectively delivering articles to predetermined of said receptacles, rst detecting means adjacent said conveyor for detecting the height of an article carried by said conveyor, second detecting means adjacent said conveyor to detect the length of the article and the position of the article along the conveyor path, a plurality of individual scanners for detecting the presence and location of distinctive markings carried by said article disposed in predetermined relationship to said iirst and second detecting means and said conveyor, logic circuits coupled to said rst and second detecting means to simultaneously receive signals from both said iirst and second detecting means and adapted to select only particular ones of said plurality of individual scanners to examine only particular areas on said article for the presence of said markings thereon depending on the size and yorientation of said article, control means for controlling said switches and selectively coupled to said individual scanners by said logic circuits whereby said articles are selectively routed to appropriate of said receptacles dependent upon the presence and Vlocation of said marking thereon.

15. Article sorting apparatus according to claim 14 wherein said rst detecting means comprises a rst plurality of spaced radiant energy-responsive elements, a plurality of sources of radiant energy each source in cooperating position with a diierent one of said radiant energy-responsive elements, said elements disposed at predetermined vertical distances above said conveyor, said second detecting means comprises a second plurality of spaced radiant energy responsive elements, a second plurality of sources of radiant energy each source in cooperating position with a diferent one of said radiant energy responsive elements, said second plurality of elements dis- Vposed predetermined distances from each other in a line parallel to said conveyor; `and wherein said plurality of individual scanners comprises at least four individual scanners each disposed a different vertical distance above said conveyor.

16. Article sorting apparatus according to claim l5 wherein said plurality of Vindividual scanners comprises at least two individual scanners disposed at the same point along said conveyor path and at least two other individual scanners disposed at a further point along said conveyor path spaced apart from said first two individual scanners.

17. Article sorting apparatus according to claim 14 wherein said plurality of individual scanners is disposed in spaced relationship with respect to said conveyor and said first and second kdetecting means so that both the upper and the lower edges of said article may be simultaneously scanned to detect the presence of said markings thereon.

18. A scanning system for examining articles having a plurality of markings thereonrsaid articles having one distinctive marking thereon which is in a predetermined but unknown area on ,said article and said article having extraneous markings thereon which are located outside of said predetermined area, said system comprising means to convey said article past said scanning system, rst photoelectric detecting means for detecting the height of the article, second photoelectric detecting means tor determining the length of the article and its position along said conveying path, a plurality of individual photoelectric scanners for detecting the presence and location of only said distinctive markings in said particular area of said articles, logic means coupled to said first and said second detecting means to simultaneously receive signals from said rst and second detecting means said logic means being adapted to se ect only particular ones of said plurality of individual scanners to examine said article tor said distinctive markings, output means selectively coupled to said individual scanners by said logic means to indicate the presence of said distinctive markings whereby said scanning system is responsive to only the presence andl absence of said distinctive markings in said particular area on said articles and whereby said scanning system is not responsive to said extraneous markings on said article.

References Cited in the le of this patent UNITED STATES PATENTS 1,729,521 Roddy Sept. 24, 1929 2,020,925 Young Nov. 12, 1935 2,033,645 Parkhill Mar. 10, 1936 2,609,928 Doust Sept. 9, 1952 2,736,431 Coleman et al. Feb. 28, 1956 2,936,886 Harmon May 17, 1960 FOREIGN PATENTS A675,556 Great Britain .luly 16, 1952 682,303 Great Britain Nov. 5, 1952 

